2. The method of claim 1 further comprising:controlling a receiver in the
user equipment to have on periods and off periods;transmitting a request
for an uplink transmission resource to transmit the uplink data;wherein
transmitting the request for the uplink transmission resource, and
transmitting the uplink data are both performed irrespective of the on
and off periods of the receiver.

3. The method of claim 2 further comprising:receiving signalling to
configure the user equipment to be able to transmit the request for the
uplink transmission resource and to transmit the uplink data irrespective
of the on and off periods of the receiver.

4. The method of claim 1 further comprising:maintaining a definition of an
available set of uplink reference signal transmission
opportunities;wherein continuing uplink reference signal transmission
until completion of transmission of the uplink data comprises
transmitting uplink reference signal transmissions until a last of the
available set of uplink reference signal transmission opportunities that
occurs during uplink data transmission and then discontinuing uplink
reference signal transmission.

5. The method of claim 1 further comprising:maintaining a definition of an
available set of uplink reference signal transmission
opportunities;making at least one retransmission in respect of the uplink
transmission;wherein continuing uplink reference signal transmission
until completion of transmission of the uplink data comprises
transmitting uplink reference signal transmission until a last of the
available set of uplink reference signal transmission opportunities that
occurs during the at least one retransmission in respect of the uplink
transmission and then discontinuing uplink reference signal transmission.

6. The method of claim 1 further comprising:maintaining a definition of an
available set of uplink reference signal transmission
opportunities;wherein continuing uplink reference signal transmission
until completion of transmission of the uplink data comprises
transmitting uplink reference signal transmission until a last of the
available set of uplink reference signal transmission opportunities that
occurs during uplink data transmission and then discontinuing uplink
reference signal transmission; the method further comprising:making a
retransmission in respect of the uplink transmission;starting uplink
reference signal transmission in anticipation of the
retransmission;continuing uplink reference signal transmission until
completion of the retransmission.

7. The method of claim 1 further comprising:receiving signalling
indicating a grant of an uplink resource to make said uplink data
transmission;starting an inactivity timer after receiving said
signalling;wherein continuing uplink reference signal transmission until
completion of transmission of the uplink data comprises continuing uplink
reference signal transmission until the inactivity timer is expired and
then discontinuing uplink reference signal transmission.

8. The method of claim 1 further comprising:transmitting a request for an
uplink transmission resource to transmit the uplink data using an
assigned scheduling request channel assignment at a next available
opportunity after the start of receipt of the uplink data.

9. The method of claim 1 further comprising:maintaining a definition of an
available set of uplink reference signal transmission
opportunities;transmitting a request for an uplink transmission resource
to transmit the uplink data;wherein starting uplink reference signal
transmission in anticipation of transmitting said uplink data comprises
starting transmitting an uplink reference signal transmission in a first
of said available set of uplink reference signal transmission
opportunities that occurs immediately after transmitting the request for
the uplink transmission resource.

10. The method of claim 9 wherein transmitting a request for an uplink
transmission resource to transmit the uplink data comprises transmitting
a request for uplink transmission using a previously assigned
semi-persistent resource.

11. The method of claim 9 wherein transmitting a request for an uplink
transmission resource to transmit the uplink data comprises transmitting
a request for uplink transmission using a contention based access
channel.

14. The method of claim 12 further comprising:receiving signalling that
contains a definition of reference signal transmission opportunities to
be made available for one or both of channel quality assessment and
timing alignment, the information identifying a minimum period for
transmission of the reference signal for channel quality assessment
and/or a minimum period for transmission of the reference signal for
timing alignment;transmitting reference signal transmissions in
accordance with the definition of transmission opportunities, and subject
to the minimum period(s) such that whenever possible a single reference
signal is sent for both channel quality assessment and timing alignment.

15. The method of claim 1 wherein each reference signal is a sounding
reference signal.

16. The method of claim 13 wherein each reference signal is a sounding
reference signal.

19. The user equipment of claim 18 wherein the uplink signal generation
module continues to generate uplink reference signals until a last of an
available set of uplink reference signal transmission opportunities that
occurs during uplink data transmission and then discontinues generating
uplink reference signals.

20. The user equipment of claim 18 wherein the uplink signal generation
module continues to generate uplink reference signals until a last of an
available set of uplink reference signal transmission opportunities that
occurs during uplink data transmission or any associated retransmissions
and then discontinues generating uplink reference signals.

Description:

BACKGROUND

[0001]In traditional wireless telecommunications systems, transmission
equipment in a base station transmits signals throughout a geographical
region known as a cell. As technology has evolved, more advanced network
access equipment has been introduced that can provide services that were
not possible previously. This advanced network access equipment might
include, for example, an enhanced node-B (eNB) rather than a base station
or other systems and devices that are more highly evolved than the
equivalent equipment in a traditional wireless telecommunications system.
Such advanced or next generation equipment is typically referred to as
long-term evolution (LTE) equipment. For LTE equipment, the region in
which a wireless device can gain access to a telecommunications network
might be referred to by a name other than "cell", such as "hot spot". As
used herein, the term "cell" will be used to refer to any region in which
a wireless device can gain access to a telecommunications network,
regardless of whether the wireless device is a traditional cellular
device, an LTE device, or some other device.

[0002]Devices that might be used by users in a telecommunications network
can include both mobile terminals, such as mobile telephones, personal
digital assistants, handheld computers, portable computers, laptop
computers, tablet computers and similar devices, and fixed terminals such
as residential gateways, televisions, set-top boxes and the like. Such
devices will be referred to herein as user equipment or UE.

[0003]In wireless communication systems, transmission from the network
access equipment (e.g., eNB) to the UE is referred to as a downlink
transmission. Communication from the UE to the network access equipment
is referred to as an uplink transmission. Wireless communication systems
generally require maintenance of timing synchronization to allow for
continued communications. Maintaining uplink synchronization can be
problematic, wasting throughput and/or decreasing battery life of a UE
given that a UE may not always have data to transmit.

BRIEF DESCRIPTION OF THE DRAWINGS

[0004]For a more complete understanding of this disclosure, reference is
now made to the following brief description, taken in connection with the
accompanying drawings and detailed description, wherein like reference
numerals represent like parts.

[0005]FIG. 1 is an illustration of a cellular network according to an
embodiment of the disclosure;

[0006]FIG. 2 is an illustration of a cell in a cellular network according
to an embodiment of the disclosure;

[0007]FIG. 3 is an illustration of a possible uplink transmission channel;

[0020]According to another broad aspect, the application provides a user
equipment comprising: a receive module; an uplink signal generation
module that starts generating the uplink reference signal in anticipation
of transmitting uplink data and continues to generate uplink reference
signals until completion of transmission of the uplink data; and a
transmit module configured to transmit the uplink data and to transmit
the uplink reference signals generated by the uplink signal generation
module.

[0021]It should be understood at the outset that although illustrative
implementations of one or more embodiments of the present disclosure are
provided below, the disclosed systems and/or methods may be implemented
using any number of techniques, whether currently known or in existence.
The disclosure should in no way be limited to the illustrative
implementations, drawings, and techniques illustrated below, including
the exemplary designs and implementations illustrated and described
herein, but may be modified within the scope of the appended claims along
with their full scope of equivalents.

[0022]FIG. 1 illustrates an exemplary cellular network 100 according to an
embodiment of the disclosure. The cellular network 100 may include a
plurality of cells 1021, 1022, 1023, 1024, 1025,
1026, 1027, 1028, 1029, 10210, 10211,
10212, 10213, and 10214 (collectively referred to as cells
102). As is apparent to persons of ordinary skill in the art, each of the
cells 102 represents a coverage area for providing cellular services of
the cellular network 100 through communication from a network access
equipment (e.g., eNB). While the cells 102 are depicted as having
non-overlapping coverage areas, persons of ordinary skill in the art will
recognize that one or more of the cells 102 may have partially
overlapping coverage with adjacent cells. In addition, while a particular
number of the cells 102 are depicted, persons of ordinary skill in the
art will recognize that a larger or smaller number of the cells 102 may
be included in the cellular network 100.

[0023]One or more UEs 10 may be present in each of the cells 102. Although
only one UE 10 is depicted and is shown in only one cell 10212, it
will be apparent to one of skill in the art that a plurality of UEs 10
may be present in each of the cells 102. A network access equipment 20 in
each of the cells 102 performs functions similar to those of a
traditional base station. That is, the network access equipments 20
provide a radio link between the UEs 10 and other components in a
telecommunications network. While the network access equipment 20 is
shown only in cell 10212, it should be understood that network
access equipment would be present in each of the cells 102.

[0024]FIG. 2 depicts a more detailed view of the cell 10212. The
network access equipment 20 in cell 10212 may promote communication
via a transmitter 27, a receiver 29, and/or other well known equipment.
Similar equipment might be present in the other cells 102. A plurality of
UEs 10 are present in the cell 10212, as might be the case in the
other cells 102. In the present disclosure, the cellular systems or cells
102 are described as engaged in certain activities, such as transmitting
signals; however, as will be readily apparent to one skilled in the art,
these activities would in fact be conducted by components comprising the
cells.

[0025]In each cell, the transmissions from the network access equipment 20
to the UEs 10 are referred to as downlink transmissions, and the
transmissions from the UEs 10 to the network access equipment 20 are
referred to as uplink transmissions. The UE may include any device that
may communicate using the cellular network 100. For example, the UE may
include devices such as a cellular telephone, a laptop computer, a
navigation system, or any other devices known to persons of ordinary
skill in the art that may communicate using the cellular network 100.

[0026]The format of an example of an uplink channel is shown schematically
in FIG. 3. The transmission can be one of a number of different
bandwidths (e.g., 1.25, 5, 15, or 20 MHz). In the time domain, the uplink
is broken into frames, sub-frames and slots. Each slot 201 (shown as
slots 2011, 2012, . . . , 20119, 20120, collectively
slots 201) is made up of seven orthogonal frequency division multiplexed
(OFDM) symbols 203. Two slots 201 make up a sub-frame 205 (sub-frames
2051, 2052, . . . , 20510, collectively are sub-frames
205). A frame is a collection of 10 contiguous sub-frames. Because the
exact details of a sub-frame 205 may very depending upon the exact
implementation, the following description is provided as an example only.
The UE will transmit using a constant-amplitude and zero-autocorrelation
(CAZAC) sequence so that more than one UE may transmit simultaneously.
The demodulation (DM) reference symbol (RS) is placed on the fourth
symbol 209 of each slot; and the control channel 211 is taken up by at
least one resource block on the very outside edges of the frequency band.

[0027]Uplink reference signal transmission opportunities for channel
quality assessment and/or timing alignment (e.g. SRS (sounding reference
signal)) transmission opportunities may exist anywhere in each sub-frame
205 and most likely at the beginning, or end. Each such transmission
opportunity is broken down into several blocks of 12 sub-carriers that
correspond to the same frequency bandwidth as a resource block. A UE may
use one or all of those frequency blocks depending on the transmission
bandwidth selected. The UE may also use every other sub-carrier in one or
more multiple blocks. In the illustrated example, an SRS is shown in the
first symbol 207 of the sub-frame 2051 and of sub-frame 20119.
FIG. 3 also shows where in time and frequency that the physical uplink
control channel (PUCCH) 211 is placed. Control signaling takes place in
the PUCCH. In one embodiment, the system implements a hybrid automatic
repeat request (HARQ) acknowledgement (ACK)/negative acknowledgement
(NACK) feedback. An ACK or NACK is sent on the PUCCH 211 by the UE to the
eNB to indicate whether a packet transmitted from the eNB was received at
that UE. The physical uplink shared channel (PUSCH) is used to send user
data.

[0028]The above description of the uplink channel is one implementation of
an uplink channel. It will be appreciated that other uplink channel
configurations may be used wherein an uplink reference signal
transmission (e.g., SRS) is sent during any portion of the uplink
message, not necessarily only at the beginning or end of a specified time
interval (e.g., slot).

[0029]In order to maintain uplink synchronization, it is desirable for the
network access equipment 20 (shown in FIG. 1) to calculate the uplink
channel conditions by analyzing signals sent from the UE 10. One possible
timing diagram of signals sent between the network access equipment 20
and the UE 10 is shown in FIG. 4, In this embodiment, the network access
equipment 20 instructs the UE 10 when to send an uplink reference signal
transmission (e.g., SRS), through use of an uplink reference signal
transmission instruction message 241. The uplink reference signal
transmission instruction message 241 may include any one of a variety of
instructions. For example, the network access equipment 20 may instruct
the UE 10 via the reference signal transmission instruction message 241
to send the reference signal transmissions at a constant rate, or in
bursts depending on the velocity of the UE 10 relative to the network
access equipment 20. In response 243, the UE 10 may send the reference
signal transmissions (e.g., SRS) in accordance with the instructions of
the network access equipment 20.

[0030]In order to conserve battery power in the UE, the UE may operate
with discontinuous reception (DRX). Typically, the UE will turn its
reception capability on and off in a repeating fashion. The network is
aware of the DRX behavior and makes its transmission to the UE during
periods that the reception capability is on. An On period followed by an
Off period is a DRX cycle.

[0031]DRX in Connected Mode will be configured by the network. Part of the
configuration is the setting of the DRX-cycle On Duration, inactivity
timers and HARQ timer. During the On periods (periods the receiver is on
each having a length specified by the On Duration), the UE will monitor
the PDCCH (packet data control channel) or configured resource for the
allocation of possible downlink and uplink transmissions. When a PDCCH is
decoded successfully, an inactivity timer will be started. At the end of
the On period, the UE may go back to sleep according to the DRX
configuration. Transmission of Uplink Reference Signal in Anticipation of
Uplink Transmission

[0032]In some embodiments, the UE does not transmit an uplink reference
signal until it determines that it has uplink data to send. Upon making
such a determination, the UE transmits the uplink reference signal in
anticipation of the uplink transmission, for example slightly before the
start of the uplink transmission, and during the uplink transmission. The
UE then stops transmitting the uplink reference signal after completion
of the uplink transmission. A flowchart of the method will be described
with reference to FIG. 5. The method begins with controlling a receiver
in the user equipment to have on periods and off periods at block 5-1.
Note that these on and off periods may for the most part be periodic or
for the most part periodic in some embodiments, but more generally they
need not be necessarily periodic. The method continues in block 5-2 with
starting uplink reference signal transmission in anticipation of
transmitting uplink data. The method continues at block 5-3 with the user
equipment transmitting uplink data after having started uplink reference
signal transmission. At block 54, the user equipment continues uplink
reference signal transmission until completion of transmission of the
uplink data.

[0033]The embodiment of FIG. 5 assumes that the uplink reference signal
transmission in anticipation of uplink data transmission is in the
context of DRX control of the receiver. In another embodiment, blocks
5-2,5-3,5-4 are executed by a user equipment that is not operating in DRX
mode in which case block 5-1 can be omitted.

[0034]Referring now to FIG. 6, a specific example will be described. In
this example and all of the examples that follow, the reference signals
are assumed to be SRS transmissions. It is to be understood that all of
the examples given have application more generally to reference signals.
FIG. 6 shows the timing of various signals for a UE in DRX mode. Shown is
DRX timing 800 for a DRX cycle assignment, timing 810 for availability of
data for transmission, timing 822 for uplink data transmission, a
scheduling request timing indicated at 830, and SRS timing indicated at
820. The DRX timing 800 consists of a DRX cycle 802 that includes a DRX
On Duration (indicated at 804) and a DRX Off Duration. The receiver is
alternately turned on for On periods having the DRX On Duration and off
for Off periods having the DRX Off Duration. The SRS timing 820 has an
SRS period 822. This represents the timing of an uplink resource that is
available for SRS transmission. More generally, the UE maintains a
definition of an available set of uplink reference signal transmission
opportunities. In some embodiments, information defining these
transmission opportunities is contained in signalling information
transmitted to the UE by the network. In the illustrated example, the
uplink resource is a periodic resource but in other embodiments, the
resource is not necessarily periodic. In the illustrated example, there
is a ratio of 12 SRS periods to one DRX cycle 802 but this is
implementation specific. As described below, an SRS is not transmitted at
every opportunity. The timing 810 of the availability of data to be sent
on the uplink may for example indicate when data arrives in a buffer for
transmission. For the purpose of this example, it is assumed that data is
available at 812 for transmission on the uplink. For the specific example
indicated, the scheduling request timing 830 shows a scheduling request
transmitted by the UE at 832 in respect of the data available at 812. In
some embodiments, a scheduling request is an indication sent by the UE to
the base station to request a previously assigned uplink resource that
may be semi-persistent in nature; this means that the same resource is
assigned each time the UE requests the resource so that details of the
assignment do not need to be signaled each time. The timing of the
resulting uplink data transmission is indicated at 825. The uplink
transmission may for example occur using a semi-persistent resource. More
generally, for the example of FIG. 6, the SRS behaviour can be in respect
of any uplink transmission; this may involve transmissions using a
semi-persistent resource, or dynamically scheduled transmissions to name
a few examples.

[0035]In the illustrated example, data arrives at 812 for transmission on
the uplink between DRX On Durations. Rather than waiting until the next
On Duration to transmit the SR at 832, the UE is allowed to transmit when
it receives data for transmission. In some embodiments, the UE transmits
the SR (more generally the UE requests an uplink transmission resource
using some request mechanism) using an assigned scheduling request
channel assignment at the next available opportunity after the start of
receipt of data for uplink transmission. In some embodiments, in the
event DRX control has the receiver off when the SR is transmitted, the UE
will turn on its receiver in order to receive an uplink grant. The
request may for example be sent using an uplink resource previously
assigned for that purpose; it may be a dedicated resource for a given UE
or a contention-based resource to name a few examples. This may reduce
average UL latencies and problems with channel congestion during On
Durations Cycles that may occur when the UE is restricted to transmitting
during DRX On Cycle Durations. In such embodiments, the request for the
uplink transmission resource and the subsequent transmission of the
uplink data are both performed irrespective of the on and off periods of
the receiver. In some embodiments, the network transmits signalling to
the UE to configure the user equipment to be able to transmit the request
for the uplink transmission resource and to transmit the uplink data
irrespective of the on and off periods of the receiver. In other
embodiments, the UE is able to behave in this manner without receiving
signalling from the network.

[0036]SRS transmission is triggered in anticipation of data transmission
825. Specifically, as shown, SRS transmission occurs over a period 824
which encompasses the timing of the uplink data transmission 825. After
data arrives to be sent by the UE, the SRS is transmitted. The SRS
transmission starts before data transmission starts and is discontinued
after the data has been transmitted. In some embodiments, this involves
continuing uplink reference signal transmission until a last of the
available set of uplink reference signal transmission opportunities that
occur during uplink data transmission and then discontinuing reference
signal transmission as shown for the example of FIG. 6.

[0037]In some embodiments, after transmission of an SR (such as at 832),
the network responds with an uplink grant on a downlink control channel,
such as the PDCCH (packet data control channel) described in TS 36.211
(see section 6) hereby incorporated by reference in its entirety. In some
embodiments, an inactivity timer is used to control when to discontinue
SRS transmission. For example, receipt of the uplink grant may be used as
a trigger to start an inactivity timer. The SRS transmission is
discontinued after the inactivity timer expires.

[0038]In some embodiments, the UE starts making SRS transmissions at the
closest SRS transmission opportunity in the uplink before making an
uplink resource request. In such embodiments, the mobile device maintains
a definition of a set of available SRS transmission opportunities as
described previously. The latest of these opportunities that occurs prior
to making an uplink resource request is the one within which the SRS
transmission starts. The example of FIG. 6 illustrates this. It can be
seen that SRS transmission opportunity 825 is the latest SRS transmission
opportunity that occurs prior to transmitting the SR at 832.

[0039]In some embodiments, this behaviour is in respect of an uplink
resource request for a semi-persistent resource; this may for example
involve using the above described SR mechanism; in some embodiments, this
behaviour is in respect of an uplink resource request that is a
transmitted using a contention based access mechanism (for example the
RACH (random access channel) mechanism described in TS 36.211 (see
section 5); finally, in some embodiments, both the SR and contention
based resource request mechanisms are available to trigger this
behaviour.

[0040]Various mechanisms have been described to trigger the start of SRS
transmission in anticipation of data transmission. Various mechanisms are
also provided to stop SRS transmission. The first example was described
above and involved starting an inactivity timer upon receipt of an uplink
grant; the SRS transmission stops upon expiry of the inactivity timer.

[0041]In another embodiment, the UE will simply stop the SRS transmission
at the end of the data transmission; in some embodiments at the earliest
opportunity after data transmission has finished.

[0042]In some embodiments, SRS is transmitted during an original data
transmission and any retransmissions/HARQ processes that may follow. The
SRS transmission is transmitted from before data transmission until
completion of any retransmissions/HARQ processes.

[0043]In other embodiments, the SRS transmission is transmitted from
before transmission of an original data transmission until completion of
the original data transmission after which SRS transmission is stopped.
In the event that retransmissions are necessary, SRS transmission is
restarted in order to cover the retransmissions. As in the case for
original transmissions, this starts in anticipation of the retransmission
and continues until completion of the retransmission.

Reference Signal Timing Alignment

[0044]In some embodiments, reference signal transmissions are made for two
different purposes:

[0045]a) to allow the network to assess the quality of the uplink channel
so that the network can determine an appropriate adaptive modulation and
encoding for uplink transmissions;

[0046]b) uplink timing alignment, as described previously.

The transmissions are the same in either case, but the network may need
them with differing timing constraints. For example, the network may need
the reference signal for uplink channel quality assessment more
frequently than for uplink timing alignment. In some embodiments, rather
than the UE making these reference signal transmissions for timing
alignment independently of reference signal transmissions for uplink
channel assessment, the UE aligns the timing of these two reference
signal transmissions whenever possible and when the timing is aligned,
only a single reference signal transmission is made.

[0047]Specifically, the network assigns the UE reference signal
transmission opportunities for timing alignment and reference signal
transmission opportunities for uplink channel quality assessment. For
each reference signal transmission opportunity, a single reference signal
is transmitted if the current opportunity is aligned with one or both of
the timing alignment or uplink channel quality assessment requirements.
In some embodiments, this reference signal behaviour is predicated on
reference signal transmission being enabled, for example using any of the
mechanisms described in previous embodiments. A specific example of this
method from the perspective of the UE will be described with reference to
the flowchart of FIG. 7. The method begins at block 7-1 with the UE
receiving signalling that allocates reference signal transmission
opportunities for uplink timing alignment and reference signal
transmission opportunities for uplink channel quality assessment. Some of
the reference signal transmission opportunities for uplink timing
alignment may coincide with reference signal transmission opportunities
for uplink channel quality assessment. The method continues at block 7-2
with transmitting reference signal transmissions for uplink timing
alignment in accordance with the signalling, and at block 7-3
transmitting reference signal transmissions for uplink channel quality
assessment in accordance with the signalling. In so doing, transmitting
reference signal transmissions for uplink timing alignment in accordance
with the signalling and transmitting reference signal transmissions for
uplink channel quality assessment in accordance with the signalling is
achieved by transmitting a single reference signal transmission for both
uplink timing alignment and uplink channel quality assessment for any
reference signal transmission opportunities for uplink timing alignment
that coincide with reference signal transmission opportunities for uplink
channel quality assessment.

[0048]An example of this method from the perspective of the network will
be described with reference to the flowchart of FIG. 8. The method begins
at block 8-1 with the network transmitting signalling that allocates
reference signal transmission opportunities for uplink timing alignment
and reference signal transmission opportunities for uplink channel
quality assessment. The method continues at block 8-2 with receiving
reference signal transmissions for uplink timing alignment in accordance
with the signalling, and at block 8-3 receiving reference signal
transmissions for uplink channel quality assessment in accordance with
the signalling. In so doing, receiving reference signal transmissions for
uplink timing alignment in accordance with the signalling and receiving
reference signal transmissions for uplink channel quality assessment in
accordance with the signalling comprised receiving a single reference
signal transmission for both uplink timing alignment and uplink channel
quality assessment for any reference signal transmission opportunities
for uplink timing alignment that coincide with reference signal
transmission opportunities for uplink channel quality assessment.

[0049]In some embodiments, the network transmits signalling information
that contains a definition of reference signal transmission opportunities
to be made available for one or both of channel quality assessment and
timing alignment. In addition, the signalling information includes
information identifying a minimum period for transmission of the
reference signal for channel quality assessment and/or a minimum period
for transmission of the reference signal for timing alignment. The UE
makes reference signal transmissions in accordance with the definition of
reference signal transmission opportunities, and subject to the minimum
period(s) such that whenever possible a single reference signal is sent
for both channel quality assessment and timing alignment.

[0050]As a specific example, consider that a basic set of SRS transmission
opportunities may be defined with a periodicity of 10 ms; the SRS for
channel quality assessment may be required every 10 ms while the UE is
transmitting; the SRS for timing alignment may be required every 30 ms
irrespective of whether the UE is transmitting. This information is used
by the UE to send a single SRS every 10 ms while the UE is transmitting
in satisfaction of both requirements, and a single SRS every 30 ms while
the UE is not transmitting.

[0051]In some embodiments, in order to carry out the above process, the UE
10 comprises a processor capable of performing the above process. For
simplicity, the different functions have been broken out into different
modules. These modules may be implemented separately or together.
Further, these modules may be implemented in hardware, software, or some
combination. Finally, these modules may reside in different portions of
the UE memory. As illustrated in FIG. 9, the UE processor comprises a
receive module 801, an uplink reference signal generation module 803, and
a transmission module 807. The receive module 801 receives communications
from the network. These may for example include a message or messages
configuring the on and off periods for the receiver, and configuring
various resources for the receiver, such as the transmission
opportunities for the uplink reference signal, and uplink grants. The
transmission module 807 makes uplink transmissions, including data
transmissions and uplink timing alignment signal transmissions. These can
be part of an integrated frame structure as described previously with
reference to FIG. 3 by way of example. The uplink reference signal
generation module 803 generates uplink reference signal transmissions for
transmission by the transmission module 807 such that uplink reference
signal transmissions occur in anticipation of and during data
transmissions. This can occur using any of the methods described earlier,
for example.

[0052]FIG. 10 illustrates a wireless communications system including an
embodiment of the UE 10. The UE 10 is operable for implementing aspects
of the disclosure, but the disclosure should not be limited to these
implementations. Though illustrated as a mobile phone, the UE 10 may take
various forms including a wireless handset, a pager, a personal digital
assistant (PDA), a portable computer, a tablet computer, or a laptop
computer. Many suitable devices combine some or all of these functions.
In some embodiments of the disclosure, the UE 10 is not a general purpose
computing device like a portable, laptop or tablet computer, but rather
is a special-purpose communications device such as a mobile phone, a
wireless handset, a pager, a PDA, or a telecommunications device
installed in a vehicle. In another embodiment, the UE 10 may be a
portable, laptop or other computing device. The UE 10 may support
specialized activities such as gaming, inventory control, job control,
and/or task management functions, and so on.

[0053]The UE 10 includes a display 402. The UE 10 also includes a
touch-sensitive surface, a keyboard or other input keys generally
referred as 404 for input by a user. The keyboard may be a full or
reduced alphanumeric keyboard such as QWERTY, Dvorak, AZERTY, and
sequential types, or a traditional numeric keypad with alphabet letters
associated with a telephone keypad. The input keys may include a track
wheel, an exit or escape key, a trackball, and other navigational or
functional keys, which may be inwardly depressed to provide further input
function. The UE 10 may present options for the user to select, controls
for the user to actuate, and/or cursors or other indicators for the user
to direct.

[0054]The UE 10 may further accept data entry from the user, including
numbers to dial or various parameter values for configuring the operation
of the UE 10. The UE 10 may further execute one or more software or
firmware applications in response to user commands. These applications
may configure the UE 10 to perform various customized functions in
response to user interaction. Additionally, the UE 10 may be programmed
and/or configured over-the-air, for example from a wireless base station,
a wireless access point, or a peer UE 10.

[0055]Among the various applications executable by the UE 10 are a web
browser, which enables the display 402 to show a web page. The web page
may be obtained via wireless communications with a wireless network
access node, a cell tower, a peer UE 10, or any other wireless
communication network or system 400. The network 400 is coupled to a
wired network 408, such as the Internet. Via the wireless link and the
wired network, the UE 10 has access to information on various servers,
such as a server 410. The server 410 may provide content that may be
shown on the display 402. Alternately, the UE 10 may access the network
400 through a peer UE 10 acting as an intermediary, in a relay type or
hop type of connection.

[0056]FIG. 11 shows a block diagram of the UE 10. While a variety of known
components of UEs 10 are depicted, in an embodiment a subset of the
listed components and/or additional components not listed may be included
in the UE 10. The UE 10 includes a digital signal processor (DSP) 502 and
a memory 504. As shown, the UE 10 may further include an antenna and
front end unit 506, a radio frequency (RF) transceiver 508, an analog
baseband processing unit 510, a microphone 512, an earpiece speaker 514,
a headset port 516, an input/output interface 518, a removable memory
card 520, a universal serial bus (USB) port 522, a short range wireless
communication sub-system 524, an alert 526, a keypad 528, a liquid
crystal display (LCD), which may include a touch sensitive surface 530,
an LCD controller 532, a charge-coupled device (CCD) camera 534, a camera
controller 536, and a global positioning system (GPS) sensor 538. In an
embodiment, the UE 10 may include another kind of display that does not
provide a touch sensitive screen. In an embodiment, the DSP 502 may
communicate directly with the memory 504 without passing through the
input/output interface 518.

[0057]The DSP 502 or some other form of controller or central processing
unit operates to control the various components of the UE 10 in
accordance with embedded software or firmware stored in memory 504 or
stored in memory contained within the DSP 502 itself. In addition to the
embedded software or firmware, the DSP 502 may execute other applications
stored in the memory 504 or made available via information carrier media
such as portable data storage media like the removable memory card 520 or
via wired or wireless network communications. The application software
may comprise a compiled set of machine-readable instructions that
configure the DSP 502 to provide the desired functionality, or the
application software may be high-level software instructions to be
processed by an interpreter or compiler to indirectly configure the DSP
502.

[0058]The antenna and front end unit 506 may be provided to convert
between wireless signals and electrical signals, enabling the UE 10 to
send and receive information from a cellular network or some other
available wireless communications network or from a peer UE 10. In an
embodiment, the antenna and front end unit 506 may include multiple
antennas to support beam forming and/or multiple input multiple output
(MIMO) operations. As is known to those skilled in the art, MIMO
operations may provide spatial diversity which can be used to overcome
difficult channel conditions and/or increase channel throughput. The
antenna and front end unit 506 may include antenna tuning and/or
impedance matching components, RF power amplifiers, and/or low noise
amplifiers.

[0059]The RF transceiver 508 provides frequency shifting, converting
received RF signals to baseband and converting baseband transmit signals
to RF. In some descriptions a radio transceiver or RF transceiver may be
understood to include other signal processing functionality such as
modulation/demodulation, coding/decoding, interleaving/de-interleaving,
spreading/de-spreading, inverse fast Fourier transforming (IFFT)/fast
Fourier transforming (FFT), cyclic prefix appending/removal, and other
signal processing functions. For the purposes of clarity, the description
here separates the description of this signal processing from the RF
and/or radio stage and conceptually allocates that signal processing to
the analog baseband processing unit 510 and/or the DSP 502 or other
central processing unit. In some embodiments, the RF Transceiver 508,
portions of the Antenna and Front End 506, and the analog baseband
processing unit 510 may be combined in one or more processing units
and/or application specific integrated circuits (ASICs).

[0060]The analog baseband processing unit 510 may provide various analog
processing of inputs and outputs, for example analog processing of inputs
from the microphone 512 and the headset 516 and outputs to the earpiece
514 and the headset 516. To that end, the analog baseband processing unit
510 may have ports for connecting to the built-in microphone 512 and the
earpiece speaker 514 that enable the UE 10 to be used as a cell phone.
The analog baseband processing unit 510 may further include a port for
connecting to a headset or other hands-free microphone and speaker
configuration. The analog baseband processing unit 510 may provide
digital-to-analog conversion in one signal direction and
analog-to-digital conversion in the opposing signal direction. In some
embodiments, at least some of the functionality of the analog baseband
processing unit 510 may be provided by digital processing components, for
example by the DSP 502 or by other central processing units.

[0061]The DSP 502 may perform modulation/demodulation, coding/decoding,
interleaving/de-interleaving, spreading/de-spreading, inverse fast
Fourier transforming (IFFT)/fast Fourier transforming (FFT), cyclic
prefix appending/removal, and other signal processing functions
associated with wireless communications. In an embodiment, for example in
a code division multiple access (CDMA) technology application, for a
transmitter function the DSP 502 may perform modulation, coding,
interleaving, and spreading, and for a receiver function the DSP 502 may
perform de-spreading, de-interleaving, decoding, and demodulation. In
another embodiment, for example in an orthogonal frequency division
multiplex access (OFDMA) technology application, for the transmitter
function the DSP 502 may perform modulation, coding, interleaving,
inverse fast Fourier transforming, and cyclic prefix appending, and for a
receiver function the DSP 502 may perform cyclic prefix removal, fast
Fourier transforming, de-interleaving, decoding, and demodulation. In
other wireless technology applications, yet other signal processing
functions and combinations of signal processing functions may be
performed by the DSP 502.

[0062]The DSP 502 may communicate with a wireless network via the analog
baseband processing unit 510. In some embodiments, the communication may
provide Internet connectivity, enabling a user to gain access to content
on the Internet and to send and receive e-mail or text messages. The
input/output interface 518 interconnects the DSP 502 and various memories
and interfaces. The memory 504 and the removable memory card 520 may
provide software and data to configure the operation of the DSP 502.
Among the interfaces may be the USB interface 522 and the short range
wireless communication sub-system 524. The USB interface 522 may be used
to charge the UE 10 and may also enable the UE 10 to function as a
peripheral device to exchange information with a personal computer or
other computer system. The short range wireless communication sub-system
524 may include an infrared port, a Bluetooth interface, an IEEE 802.11
compliant wireless interface, or any other short range wireless
communication sub-system, which may enable the UE 10 to communicate
wirelessly with other nearby mobile devices and/or wireless base
stations.

[0063]The input/output interface 518 may further connect the DSP 502 to
the alert 526 that, when triggered, causes the UE 10 to provide a notice
to the user, for example, by ringing, playing a melody, or vibrating. The
alert 526 may serve as a mechanism for alerting the user to any of
various events such as an incoming call, a new text message, and an
appointment reminder by silently vibrating, or by playing a specific
pre-assigned melody for a particular caller.

[0064]The keypad 528 couples to the DSP 502 via the interface 518 to
provide one mechanism for the user to make selections, enter information,
and otherwise provide input to the UE 10. The keyboard 528 may be a full
or reduced alphanumeric keyboard such as QWERTY, Dvorak, AZERTY and
sequential types, or a traditional numeric keypad with alphabet letters
associated with a telephone keypad. The input keys may include a track
wheel, an exit or escape key, a trackball, and other navigational or
functional keys, which may be inwardly depressed to provide further input
function. Another input mechanism may be the LCD 530, which may include
touch screen capability and also display text and/or graphics to the
user. The LCD controller 532 couples the DSP 502 to the LCD 530.

[0065]The CCD camera 534, if equipped, enables the UE 10 to take digital
pictures. The DSP 502 communicates with the CCD camera 534 via the camera
controller 536. In another embodiment, a camera operating according to a
technology other than Charge Coupled Device cameras may be employed. The
GPS sensor 538 is coupled to the DSP 502 to decode global positioning
system signals, thereby enabling the UE 10 to determine its position.
Various other peripherals may also be included to provide additional
functions, e.g., radio and television reception.

[0066]FIG. 12 illustrates a software environment 602 that may be
implemented by the DSP 502. The DSP 502 executes operating system drivers
604 that provide a platform from which the rest of the software operates.
The operating system drivers 604 provide drivers for the wireless device
hardware with standardized interfaces that are accessible to application
software. The operating system drivers 604 include application management
services ("AMS") 606 that transfer control between applications running
on the UE 10. Also shown in FIG. 12 are a web browser application 608, a
media player application 610, and Java applets 612. The web browser
application 608 configures the UE 10 to operate as a web browser,
allowing a user to enter information into forms and select links to
retrieve and view web pages. The media player application 610 configures
the UE 10 to retrieve and play audio or audiovisual media. The Java
applets 612 configure the UE 10 to provide games, utilities, and other
functionality. A component 614 might provide functionality related to the
present disclosure.

[0067]The UEs 10, ENBs 20, and central control 110 of FIG. 1 and other
components that might be associated with the cells 102 may include any
general-purpose computer with sufficient processing power, memory
resources, and network throughput capability to handle the necessary
workload placed upon it. FIG. 13 illustrates a typical, general-purpose
computer system 700 that may be suitable for implementing one or more
embodiments disclosed herein. The computer system 700 includes a
processor 720 (which may be referred to as a central processor unit or
CPU) that is in communication with memory devices including secondary
storage 750, read only memory (ROM) 740, random access memory (RAM) 730,
input/output (I/O) devices 700, and network connectivity devices 760. The
processor may be implemented as one or more CPU chips.

[0068]The secondary storage 750 is typically comprised of one or more disk
drives or tape drives and is used for non-volatile storage of data and as
an over-flow data storage device if RAM 730 is not large enough to hold
all working data. Secondary storage 750 may be used to store programs
which are loaded into RAM 730 when such programs are selected for
execution. The ROM 740 is used to store instructions and perhaps data
which are read during program execution. ROM 740 is a non-volatile memory
device which typically has a small memory capacity relative to the larger
memory capacity of secondary storage. The RAM 730 is used to store
volatile data and perhaps to store instructions. Access to both ROM 740
and RAM 730 is typically faster than to secondary storage 750.

[0070]The network connectivity devices 760 may take the form of modems,
modem banks, Ethernet cards, universal serial bus (USB) interface cards,
serial interfaces, token ring cards, fiber distributed data interface
(FDDI) cards, wireless local area network (WLAN) cards, radio transceiver
cards such as code division multiple access (CDMA) and/or global system
for mobile communications (GSM) radio transceiver cards, and other
well-known network devices. These network connectivity 760 devices may
enable the processor 720 to communicate with an Internet or one or more
intranets. With such a network connection, it is contemplated that the
processor 720 might receive information from the network, or might output
information to the network in the course of performing the
above-described method steps. Such information, which is often
represented as a sequence of instructions to be executed using processor
720, may be received from and outputted to the network, for example, in
the form of a computer data signal embodied in a carrier wave.

[0071]Such information, which may include data or instructions to be
executed using processor 720 for example, may be received from and
outputted to the network, for example, in the form of a computer data
baseband signal or signal embodied in a carrier wave. The baseband signal
or signal embodied in the carrier wave generated by the network
connectivity 760 devices may propagate in or on the surface of electrical
conductors, in coaxial cables, in waveguides, in optical media, for
example optical fiber, or in the air or free space. The information
contained in the baseband signal or signal embedded in the carrier wave
may be ordered according to different sequences, as may be desirable for
either processing or generating the information or transmitting or
receiving the information. The baseband signal or signal embedded in the
carrier wave, or other types of signals currently used or hereafter
developed, referred to herein as the transmission medium, may be
generated according to several methods well known to one skilled in the
art.

[0072]The processor 720 executes instructions, codes, computer programs,
scripts which it accesses from hard disk, floppy disk, optical disk
(these various disk-based systems may all be considered secondary storage
750), ROM 740, RAM 730, or the network connectivity devices 760. While
only one processor 720 is shown, multiple processors may be present.
Thus, while instructions may be discussed as executed by a processor, the
instructions may be executed simultaneously, serially, or otherwise
executed by one or multiple processors.

[0073]While several embodiments have been provided in the present
disclosure, it should be understood that the disclosed systems and
methods may be embodied in many other specific forms without departing
from the spirit or scope of the present disclosure. The present examples
are to be considered as illustrative and not restrictive, and the
intention is not to be limited to the details given herein. For example,
the various elements or components may be combined or integrated in
another system or certain features may be omitted, or not implemented.

[0074]Also, techniques, systems, subsystems and methods described and
illustrated in the various embodiments as discrete or separate may be
combined or integrated with other systems, modules, techniques, or
methods without departing from the scope of the present disclosure. Other
items shown or discussed as coupled or directly coupled or communicating
with each other may be indirectly coupled or communicating through some
interface, device, or intermediate component, whether electrically,
mechanically, or otherwise. Other examples of changes, substitutions, and
alterations are ascertainable by one skilled in the art and could be made
without departing from the spirit and scope disclosed herein.